Color photography



Patented Apr. 21, 1942 COLOR PHOTOGRAPHY Wilhelm Schneider and Alfred Friilich, Dessau, Germany No Drawing. Application July 13, 1939, Serial No. 284,250. In Germany July 14, 1938 3 Claims.

This invention relates to color photography and more particularly to dyestuff components for color forming development.

It has been proposed to use in the production of photographic color pictures silver halide emulsions with color formers fast to diffusion which are added in dissolved form to the silver halide emulsion but are not capable of being washed out of the emulsion. Such color formers fast to diffusion are obtained from simple dyestufl componentsby introducing into them substituents which hinder diffusion. Among other substituents having this property it has been proposed to use carbon chains having more than 5 carbon atoms. Moreover, into these dyestuif components groups lending solubility in water, for instance sulphonic acid or carboxylic acid groups have been introduced in order to make the dyestuif component soluble in water, whereby its incorporation in the emulsion is facilitated and the crystallisation, for instance before or after the application of the emulsion, is pre vented.

It is an object of the present invention to provide a method of producing novel dyestuff components for color forming development.

A further object resides in the provision of an improved emulsion for color forming development containing a novel and improved type of color former fast to diifusion.

A still further object is the provision of new color formers which are soluble in aqueous liquids but incapable of being removed from a silver halide emulsion by washing.

Still further objects will become apparent from the detailed specification following hereinafter.

This invention is based on the observation that color formers suitable for use in the production of color photographic pictures and fast to diffusion are obtained by introducing into the molecule of the color former one or more polymembered substituents in which, apart from the initial and final members, the same arrangement of carbon atoms occurs several times, and these arrangements are connected by heteroatoms. By this kind of substitution the number of color formers suitable for color development is considerably increased. The invention consists in using poly-membered substituents corresponding with the general scheme (-A-XJ, where A is a carbon chain of, for example, 2-4 carbon atoms, for instance ethylene or a homologue thereof, X is a hetero-atom or -group, for in stance oxygen, the imino group or sulphur. The

individual members of the substituent therefore consist, for example, of ethyleneor propylene radicals or similar hydrocarbon groups which are united to form a poly-membered substituent by a hetero-atom, for instance oxygen, nitrogen or sulphur, the initial member carrying a reactive group which makes it possible to unite the substituent which the molecule of the dyestuff former and the final group being a hydro-'- gen atom or any desired carbon group. Such substituents are, for example, the poly-merides of ethylene oxide, propylene oxide, ethylethylene oxide, diamethylethylene oxide, trimethylethylene oxide, oxypropylene oxide, hexylene oxide, methylpropylene oxide, isopropylethylene oxide, butylene dioxide, erythrene dioxide and other ethylene oxides containing alkyl or cycloalkyl or aryl or aralkyl radicals, as well as the halogen derivatives of these, for example epichlorhydrin, dichloropropylene oxide, epibromhydrin, p-bromethylene oxide, alkylene imines and alkylene sulphides, for example ethylene imine and ethylene sulphide, also phenoxypropene oxide, alkylpolyethoxyacetic acids, polyethylene oxide carboxylic acids, aryl-polyethylene oxide acetic acids.

The number of the several members in these poly-membered substituents which is necessary to make the coupling component fast to diffusion is dependent on the molecular size of the several members. In the case of polyethylene oxide this fastness is generally attained by a chain having about 5 to 6 structural units As color formers such compounds come into question as are suitable in the color development for forming quinoneimine or azomethine dyestuffs, for example phenols, naphthols, aminonaphthols, anilines, naphthylamines. Of these components phenols and naphthols are foremost which in the para-position, to the hydroxyl group contain no substituent or a negative substituent, the latter being eliminated during the development, for example resorcinol, meta-aminophenol, aminocresol, chloraminocresol, salicylic acid, 1 hydroxybenzene-2z6 dicarboxylic acid, metmxylenol-carboxylic acid, 2-aminophenol-4- sulphonic acid, 2-amino-6-methoxyphenol, 1:3- dihydroxynaphthalene, 1:8 dihydroxynaphthalene, 1 :2-aminonapththol, 1 :5-aminonaphthol, 4 chloro-5-amino-a-naphthol, a hydroxynaphthoic acid, 4-chloro-l-hydroxy-2-naphthoic acid, 6-amino-1-hydroxy-2-naphthoic acid, 6-methoxy-1-hydroxy-2-naphthoic acid, 2-amin-4-su1- phonic acid-a-naphthol, -amino-4-sulphonic acid-a-naphthol, 5-hydroxytetrahydroquinoline, 2-hydroxy-4'-aminodiphenyl ether, 2-hydroxy- 4-aminodiphenyl methane, G-hydyroxycinnamic acid, 4:4'-diamino-2:2'-dihydroxydiphenyl; also all bodies which have a reactive methylene group, for instance acetoacetic acid esters, cyanoacetic acid esters, benzoyl acetic acid esters, benzoyl acetonitrile, hydrindenes, pyrazolones, isoxazolones, cumaranones, hydroxythionaphthenes and others.

Furthermore, the substituents may be introduced into the color former such as those named in U. S. Patents Nos. 2,178,612; 2,186,849; 2,186,850; 2,179,244; 2,186,732; 2,156,821; 2,186,733; 2,186,851; 2,186,735; 2,186,734; 2,186,719; 2,186,852; 2,186,736; 2,200,306; 2,154,918; 2,186,045; 2,214,483; 2,186,685; 2,179,238 and U. S. P. application Serial No. 265,601, filed June 24, 1938.

The substituent which lend fastness to diffusion may be introduced directly into the molecule of the color former in various ways, for instance by the process described in German Patent 670,419. Typical reactions are as follows:

l-nitro-2-naphthol is condensed with ethylene oxide in such a manner that a polyethylene oxide chain of an average number of members at least 5 is formed whereupon the nitro-group is converted in known manner into the hydroxy-group, so that a l-naphthol-2'-polyethylene oxide ether is produced. During the condensation with ethylene oxide there are produced besides'5membered polyethylene oxide chains both some longer and shorter chains. Preferably the reaction is conducted by using a suitable excess of ethylene ing a coupling component yielding a blue picture upon color forming development. Again the amino-phenol ether may be condensed with an acylacetic acid ester and in this manner a component which is fast to diflusion yielding a yellow d ye upon color forming development is obtained. Further, a substituted pyrazolone may be made from the aminophenyl ether by way of the hydrazine; thisis suitable as a coupling com ponent for color forming development yielding a red dye. I

Instead of the nitrophenylpolyethylene oxide ether, numerous other intermediate products may be used, for example a condensation product of ethylaniline and ethylene oxide which, by subsequent nitrosation and reduction acquires an amino-group suitable for the reaction. Analogously ethylaniline may be caused to react with propylene oxide, ethylene-imine and the like.

A further possibility in making components fast to diffusion by this invention consists in condensing meta-nitrophenol with ethylene oxide, propylene oxide, butylene dioxide, or another homologue, and converting the nitro-group in g'rknown manner into the hydroxy-group. In this oxide in such a manner that longer chains than those having 5-members or structural units may be produced, but none shorter. Should the reaction produce also shorter chains than are required to ensure the fastness of the dyestufi former to diffusion these compounds may be removed in simple manner by dissolving the color former in gelatine and washing the gelatin-e before it is added to the emulsion. Alternatively a color former may be added directly to the emulsion and the emulsion washed.

Into l-nitronaphthylmethylamine ethyleneimine is introduced, so that at the secondary amino-group ethylene-imine radicles are attached to the extent of an average number. of members at least 5. After\gonversion of the nitro-group into the hydroxy-group, l-hydroxy- 2-methylpolyethylene-imine-naphthylamine is obtained.

Ethylacetoacetate is condensed with metanitraniline, the nltro-group is reduced and the amino-group thus formed is caused to react with the acid chloride from butylhepta-ethoxy-acetic acid of the formula cinuocmcm) q-ocnzcoou 2-amino-1-naphthol iscaused to react with the chloride of propylhepta-ethoxyacetic acid of the formula CaH'z(OCH2CH2) 70-CH2-COOH.

The substituents which prevent diifusion may also be introduced at an intermediate stage, for example by causing meta-nitrophenol to react with ethylene oxide in such a manner that a polyethylene oxide ether having an average number of 5 structural units is produced, whereupon the nitro-group is reduced. The aminophenol ether thus obtained may be worked up in;va:rious ways to dyestufl. components for color forming development, for instance by condensing it with e-hydroxynaphthoic acid chloride, thus obtainmanner coupling components for color forming development yielding blue dyes are obtained.

Chlorethanol is condensed with ethylene oxide or a homologue or analogue thereof in such a manner that for instance a polyethylene oxide chain with at least 8 structural units is obtained, and the chlorine is exchanged for an aminogroup by treatment with ammonia to obtain a very valuable intermediate product for dyestufi components, for instance the amino-group may be condensed with a dyestufi component containing a carboxyl group, for instance u-hydr'oxynaphthoic acid; there is thus obtained a component fast to diflusion for color forming development yielding a blue picture dye. If ethyl benzoylacetate is similarly condensed, there is obtained a coupling component for yellow.

Instead of chlorethanol, chloroethylglycol may be used, and this condensed for example with butylene oxide. By the use of this already polymembered parent material, the formation of shorter chains is automatically diminished.

A further possibility consists in using halogen ated bodies capable of polymerisation, for example epichlorhydrin. Thus, chlorethanol is condensed with epichlorhydrin in the presence of a suitable catalyst, for instance tin tetrachloride, such excess of epichlorhydrin being used that a polymeric chain of an average number of 8 members is obtained. The chlorine atoms in this chain are exchanged for amino-groups whereby the condensation with color formers containing carboxyl groups becomes possible.

Instead of chlorethanolin the preceding example, there may ,be used a compound which of itself makes the color former fast to diffusion, in which case the condensation with epichlorhydrin, besides further increasing the fastness to difiusion, lends to the compound a valuable increase in solubility and renders possible the introduction of reactive groups. For instance, dodecylalcohol is condensed with 4 mols epichlorhydrin, the chlorine atoms are exchanged for aminogroups, and the product is condensed with ahydroxynaphthoic acid chloride. There is obtained a coupling component for blue which is fast to diilfusion. Instead of epichlorhydrin there may be used, for example, dichloropropylene oxide.

' FurthQ-more, polyglycerols and polyglycols aaaonaa A special advantage of a large series of ,dye-

stulfformers produced by this invention consists in the enhanced water-solubility of the product without using special groups lending solubility thereto, for instance carboxyl groups or sulphogroups. The new color formers may for the most part be added directly in neutral solution to the silver halide emulsion.

The emulsion containing the color former fast to diffusion may be made up into photographic material in known manner, one or more layers of the emulsion being arranged on one or both sides of a carrier and superimposed if necessary.

sitized emulsions containing different color formers may be distributed in the form of small particles on a carrier.

The color picture may be produced in various ways, for example as described in U.- S. P. applications Ser. Nos. 10,704 flied March 12, 1935. 72,718 filed April 4, 1936, 94,340 filed August 5, 1936, 90,726, filed July 15, 1936, 141,093 filed May 6, 1937. In the exposed emulsion layer the picture may be developed by a simple color forming development or by reversal development as described in U. S. P. applications Ser. Nos. 148,731 filed June 17, 1937, and 100,319 filed September 11, 1936.

The following examples illustrate the invention:

Example 1.--1 nitro-2-naphthol is heated to 150 C. in an autoclave in toluene in the presence of some potassium hydroxide. Ethyleneoxide is introduced in gaseousform by means of nitrogen under pressure from a stock bottle, until the increase of, weight of the autoclave indicates that the absorption of 5 ethyleneoxide radicals by 1 mol of nitronaphthol. After the end of reaction the toluene is removed in vacuo and the residue extracted several times with ether. The remaining solid is dissolved in glacial acetic acid and reduced catalytically. The amino-group obtained is diazotised and converted into the hydroxy-group by boiling in a hydroxylated solvent. 1 kilo of silver halide emulsion is mixed with a solution of 10 grams of this 2-pentaethoxy-l-naphthol. After casting the emulsion there is obtained a silver halide layer which,

Example 2.-Butylalcohol is condensed with ethylene-oxide and the product fractionated, in which case a partial decomposition in the hyvac ethylbenzoylacetate follows.

roacetic acid ester (from dodecyialcohol and chloroacetylchloride) to form buty'lheptaetheneoxy-acetic-acid-dodecylester. The latter is freed of some dodecylchloroacetic acid ester by shaking the solution in methanol or methanol/water with ligroin. By boiling with normal sodium hydroxide solution the ester is saponiiled. The dodecylalcohol which separates is removed by shaking with ether the alkaline solution is rendared acid to Congo and evaporated until a dry residue remains. Byextrac'ting the residue with warm absolute alcohol and distilling of the solvent the butyl-heptaetheneoxy acetic acid,- a brown viscous fluid-is obtained.

Its conversion into the acid chloride is per"- formed in the presence of an'acid binding agent,

1!. i. pyridine in which case the complex compound of pyridine, acid, and thionylchloride need not be, destroyed but can be used directly for acylating aminopyrazolone. bromide emulsion is mixedwith 10 grams of 1- phenyl-3 4'-butylhepta-etheneoxyaceto aminophenyl-5-pyrazolone, and the emulsion is cast. There is obtained a silver halide layer which, on development with a developer for color forming development, yields a red dyestufl picture.

Example 3.---Ethylaniline is condensed with ethyleneimine in such a mannerthat the ethylene-imine forms a chain of an average number of 5 members; the product is nitrosated and reduced, and the reduction product condensed with ethyl acetoacetate. Of this condensation product 8 grams are added to 1 kilo of silver bromide emulsion and after casting the silver halide layer is exposed and treated with a color forming de-' veloper to produce a yellow dyestuif picture.

Example 4.3-nitro-phenol is condensed with propylene oxide in such a manner that propylene oxide ether is produced having an average number of propenoxy groups of at least 5. After reduction of the nitro-group condensation with Of this condensation product 15 grams are added to 1 kilo of silver bromide emulsion. The silver halide emulsion yields on development with dimethylaminoaniline a yellow dyestui! picture.

Example 5.-2-amino-1-naphthol is condensed with the acid chloride of a polyetheneoxy-carboxylic acid which contains an average of about 7 ethylene oxide residues. Polyetheneoxy-carboxylic acids of this kind are produced by recannot be avoided. The fractionation which by acting the sodium salt of hydroxy acetic acid ester with ethylene oxide under pressure and subsequent saponiflcation with dilute caustic soda lye.

Another method of producing the polyetheneoxycarboxylic acids consists in condensing chloroethyleneglycol in the presence of tin-tetrachloride with ethyleneoxlde, the average number of ethyleneoxide molecules which have reacted being determined by the increase in weight of the reaction product. By reacting with a cyanide the halogen atom is substituted by the CN-radical, which can be saponified to yield the carboxylic acid radical. 15 grams of this product are added to 1 kilo of a silver halide emulsion. The latter is cast. The silver halide emulsion layer yields on color forming development a blue dyestuif picture.

Example 6.Chlorethanol is condensed in presence of tin tetrachloride at about C. with ethylene oxide in such a manner that an ethylene oxide chain of about 8 members is attached. (German Patent 670,419.) The product is treated with 30-fold excess of alcoholic am- 1 kilo of silver.

, picture.

Example 8.-1-nitro-3-chlorophenol is condensed with propylene/oxide in presence of tin tetrachloride in such a manner that the phenolic methoxy-group is condensed with a chain of at least 6 propylene oxide residues. (German Patent No. 670,419.) The nitro-group is then reduced and the amino-group is condensed with a-hydroxynaphthoic acid.

Of this body 10 grams are added to 1 kilo of a silver bromide emulsion. The layer cast from the emulsion yields on color forming development 9. blue dyestuff picture. If the aminoproduct is condensed with ethylacetoacetate there is obtained a yellow coupling component. It the amino-group is converted in known manner into the hydrazine and condensed with ethylacetoacetate, there is obtained a pyrazolone. 10 grams of this pyrazolone are added to 1 kilo of silver halide emulsion, and the latter cast to yield a layer which on color forming development gives a red dyestuff picture.

Example 9. grams of a-hydroxynaphthoicacid are heated with 20 grams of polyglycerol until no more water 'distils. The condensation product formed is stirred into 100 grams of a gelatine solution of per cent strength; the gelatine solution is allowed to solidify and then washed for several hours and stirred into 300 cc.

of silver halide emulsion. When this emulsion is cast and the layer is developed by color forming development, a blue dyestufl picture is obtained.

Example 10.-Polymeric ethylene oxide having a melting point of from -60" C. is reacted with a-hydroxynaphthoic acid chloride. The conversion product is purified by repeated extraction with ether. 10 g. of this product obtained by direct reaction of color former with polymeric ethylene oxide are added to g. of gelatine solution of 10 per cent strength, whereafter the 'gelatine is washed shortly and stirred into 300 ccm. of silver halide emulsion. By casting this emulsion, layers are obtained which yield a blue dyestufi picture upon color forming development.

' We claim:

1. An unexposed silver halide gelatine emulsion containing a color former which though soluble in aqueous liquids is fast to diffusion in gelatine, said component containing at least one substituent having a chain of the general formula (-'AX) 11., wherein A is alkylene, X is a heterogroup selected from the class consisting of O--, NR, and .'S, R being H, alkyl and n is more than 5.

.2. An unexposed silver halide gelatine emulsion containing a color former which though soluble in aqueous liquids is fast to diffusion in gelatine, said component containing at least one substituent consisting of a polyalkylen-oxide chain in which the alkylene oxide group recurs more than five times.

3. An unexposed silver halide gelatine emulsion containing a color former which though soluble in aqueous liquids is fast to diffusion in gelatine, said component containing at least one substituent consisting of a polyethylene oxide chain 

